IntelliWheels, the first automatic multi-speed transmission for wheelchairs, is a significant paradigm shift in the way that manual wheelchairs can be used because it uses automatic gear changes to facilitate propulsion. The wheelchair user still pushes the hand rims forward, backward, and in opposite directions in order to turn; however the hand rims drive the 3-speed transmissions (located in each wheel hub), which in turn drive the wheels. Similar to way that people ride bicycles, gear shifting allows people to move up and down hills, over rough terrain, and over long distances in a more efficient way. Our target users are specifically the 850,000 manual wheelchair users (mWCUs) who are low-mid and mid-high functioning. This group is mostly independent and active, experiences moderate difficulty pushing a wheelchair, and can easily see how the automatic gear shifting in the IntelliWheels system would benefit them in their day-to-day life. This device has the potential to address a very pressing problem experienced by mWCUs, pain. It has been reported that shoulder pain is experienced by up to 70% of the 1.5 million manual wheelchair users in the U.S. Shoulder pain in mWCUs has been directly linked to further disability including difficulty performing activities of daily living, decreased physical activity, and reduced quality of life. Overall, any loss of upper limb function due to pain adversely impacts the independence and mobility of mWCUs. Subsequently, it is imperative to develop innovative technologies, therapies, and interventions to minimize shoulder pain. Current options for mWCUs experiencing shoulder pain include: powered wheelchairs which are heavy, expensive, and provide more assistance than is necessary for mWCUs; power assist manual wheelchairs which are heavy, expensive, and have short battery life; lever wheelchairs which are novel but fail to gain acceptance; and one 2-speed design which requires the user to manually shift gears and costs $5000. The need to manually switch gears further limits that product to individuals with sufficient cognitive function or dexterity. Therefore an add-on which allows mWCUs to continue to use their self-propelled chairs, and provides a low-cost, low-weight, multiple speed solution that does not require user input is necessary. During the requested 12-month project period, we will design and fabricate an Alpha proof-of-concept prototype and a refined Beta prototype. The Beta prototype will be redesigned to meet target specifications: weight less than 10 lbs, battery life of at least 24 hours, and manufacturable for no more than $1,500 per system. This cost allows a market price of $3,000. Additionally, the market price makes it reimbursable with standard Medicare codes. The prototypes will be put through rigorous bench-top tests in which the reliability of the mechanical and the electronic systems are tested. Finally, user feedback through focus groups and end- user demonstration testing will be studied to determine the appeal and preliminary performance of the IntelliWheels system design. PUBLIC HEALTH RELEVANCE: Shoulder pain is experienced by up to 70% of the 1.5 million manual wheelchair users in the United States. It has been directly linked to further disability including difficulty performing activities of daily living, decreased physical activity, and reduced quality of life. As the first multi-speed automatic transmission for manually propelled wheelchairs, the IntelliWheels system will revolutionize how manual wheelchair users push their wheelchairs by reducing the strain on the upper body and shoulders. The IntelliWheels system is an add-on option with two modified wheels and an electronics package that mount to any wheelchair frame.